1. Description of the Prior Art
Resonant transmission lines, also commonly referred to as RF tank cavities or RF tank circuits have been built in the past in half-wave and quarter-wave types. These circuits usually require a plate blocking capacitor to insulate the high DC potential of an associated power amplifier anode from the cavity walls, and in addition, they require insulated mechanical sliding supports for tuning. Both the half-wave and quarter-wave cavities built along these principals are more costly and have less efficiency than the folded half-wave cavity which is the subject of the present invention. Due to the folded nature of this cavity, a plate blocking capacitor is not required, and the inner conductor of the cavity may be operated at a high DC as well as a high RF potential, since tuning is accomplished without contact whatsoever with this inner conductor.
2. Field of the Invention
The field of art to which this invention pertains is RF tank circuits for amplifier stages and, in particular, to such circuits for use with power transmitters. More particularly, this invention relates to the manner of forming the tank circuit in such a way as to improve the power and efficiency as well as to effect cost reductions in the unit.